Anomeric forms of 9-(2-amino-2-deoxy- d-xylofuranosyl)adenine

Abstract

The ethyl 2-acetamido-2-deoxy-1-thio-α- d-xylofuranoside ( 1a) previously reported was further acetylated to the 3,5-diacetate ( 1b), and this was completely deacetylated by successive treatment with phosphorus pentasulfide and methanolic ammonia. After introduction of the N-(2,4-dinitrophenyl) group, replacement of the ethylthio group by chlorine yielded the glycosyl chloride derivative 6, which gave, on treatment with N-acetyl(chloromercuri)adenine and removal of all protecting groups, a crystalline mixture ( 9a) of the anomers of 9-(2-amino-2-deoxy- d-xylofuranosyl)adenine. Separation of the anomers on an ion-exchange column gave the pure, crystalline anomers ( 9b and 9c). Evidence is presented that the anomeric mixture 9a is a 1:1 molecular compound. Anomeric assignments were made on the basis of n.m.r. spectroscopic and polarimetric data, including circular dichroism.